1. Field of the Invention
The present invention relates to a method of and an apparatus for forming an outline character by processing ordinary characters, numerals, marks, etc. (hereinafter referred to as character(s)) in a display apparatus, e.g. printer, cathode ray tube, or the like.
2. Description of the Related Art
Generally, an ordinary form of characters is used in the display apparatus, but when the characters are modified, sometimes an outline character, i.e., a character from which the inner portions have been removed, to be displayed as a white space, is used. These outline characters are infrequently used, and therefore the preparation of specific character fonts for outline characters is disadvantageous from the economical viewpoint. Accordingly, when necessary, outline characters are formed by processing the fonts of ordinary characters memorized in a character generator.
As mentioned above, an outline character is formed by removing the inner portions thereof, to be displayed as a white space, and comprises peripheral portions encompassing the white spaces, and therefore, the outline character may be called an "encompassed" character.
In a conventional method of forming an outline character, first the character data is read from a character data storage means (i.e. character generator) storing the character data expressed as a dot pattern, the dot pattern of the character is then expanded peripherally by one dot, i.e., the character is widened, and subsequently, the widened character is whitened in conformance with the original character pattern.
In the conventional method of forming an outline character, however, since the widened character is removed, by the original character, which is not changed, the upper or lower periphery of the character is white and a closed or encompassed periphery thereof can not be obtained, if the original character reaches the upper or lower end of the dot display space as an underline or the like.
The following publication is related to this invention;
Japanese Unexamined Patent Publication (Kokai) No. 60-83851.